Apparatus for controllably introducing particulate material into a reactor by disturbance of the natural angle of repose thereof

ABSTRACT

An apparatus for controllably introducing particulate material into the interior of a hollow reactor housing in a predetermined particulate material flow path having a predetermined directional flow for enabling reaction of the particulate material within the housing interior includes means for collecting a pile of particulate material injected into the interior to provide a pile having an unsupported surface oriented to the horizontal at a predetermined natural angle of repose of the particulate. Means are located within the collected pile for introducing a thin stream of fluid into the interior of the collected pile from beneath the pile in the same direction as the predetermined direction of material flow to disturb the natural angle of repose equilibrium condition of the pile for impelling a portion of the collected particulate from the surface into the flow path.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of my U.S. patent application, Ser. No.223,198 filed Feb. 3, 1972, entitled "Apparatus UtilizingCounter-Current Interaction", now U.S. Pat. No. 3,876,383, issued Apr.8, 1975.

BACKGROUND OF INVENTION

1. Field of the Invention

The present invention relates to an apparatus utilizing counter-currentinteraction and such apparatus in which the rate of flow of particulatematerial in such interaction is controllably varied through theassociated material path in which such interaction occurs.

2. Description of the Prior Art

Reactors or vessels in which interaction between materials, such asthermal interaction, occur are well known. Several of these reactors areof the type in which particulate material is introduced above a plate ortray having a multiplicity of closely spaced perforations through it, agas being spaced at a temperature above or below that of the particulatebeing directed upwardly through the plate, the gas flow being sufficientto produce a turbulent bed of particulate above the plate yet permittingthe downward passage of particulate through the plate, therebyexchanging heat between the particulate and the gas. This type ofthermal interaction is based on counter-current flow. Such a reactor isdescribed in U.S. Pat. No. 3,263,346 and corresponding British Pat. No.1,102,264, both of which are herein specifically incorporated byreference in their entirety.

In such a reactor a plurality of spaced apart perforated trays or platesare normally provided, the perforations being sufficiently large so thatthe largest particles handled by the apparatus may easily pass throughthem. The particulate passes downwardly through the perforations in theplates, the upward velocity of the gas being insufficient to conveyupwardly the average particle of the particulate handled. Thus, theparticles drift downwardly towards the perforated tray at a velocitywhich is less than the settling velocity of a particle with no counterair flow, the particle being subjected to the relatively high velocityjet action of the gas passing through the perforations in the plate asthe particles approach the plate. This jet velocity is considerablyhigher than the average particle settling velocity, and, accordingly,the particles are accelerated upwardly until the jet action of the airis dissipated. This results in the creation of a turbulent bed above theplates or trays. Furthermore, in such prior art reactors, because of thespacing of the perforations in the trays, there are quiescent zonesabove the plate in which there is little or no upward air movement. Inthese zones the particles drift downwardly to the plate or tray wherethey are again subject to reentrainment in the gas and flow upwardly orpass through the perforations in the tray. The counter current flowassociated with these prior art trays is as follows.

The gas passes upwardly through a perforation in the tray and iscontracted toward the center of the aperture, thus allowing particles ofmaterial to flow downwardly through the aperture at the sides thereof.If the flow rate through the aperture is not sufficient to accommodateall the particles presenting themselves to the aperture without blockingthe aperture, the air flow is temporarily cut off and is transferred toanother unblocked aperture. As soon as the air flow stops, thetemporarily retained particles are released until blockage is eliminatedand the air flow is reestablished through the aperture. The particles ofmaterial pass downwardly through one perforated plate into anotherturbulent bed formed above the next adjacent perforated plate whereinthe same action is repeated.

In such prior art reactors, the cooling of the particles of material isdependent upon the amount of time during which the material is retainedwithin the vessel or, in other words, the amount of time provided forinteraction of the particulate and the associated material or gas withwhich interaction occurs. This retention time, in prior art reactors, isdetermined by the size of the particles, the air velocity, the number ofperforated plates positioned within the vessel, and the size and numberof the perforations in the trays. The level of each turbulent bed ofmaterial above a particular perforated plate or tray is determined bythe size of the material, the velocity of the air through theperforations, and the number and size of the perforations. Thisretention time is a critical factor dependent on the desired interactionand, in the instance of thermal interaction, is dependent on the desiredend result thermal exchange. In addition, in prior art reactorsutilizing a plurality of perforated trays, each of which allows aturbulent bed of material to be formed, the material is cooled orinteraction occurs, in what may be considered a step-by-step process,each bed providing a step in the process. Such prior art reactors,however, are not satisfactory in that they utilize presized trays whosesize has been set for a given fixed retention time dependent on thetemperature of the substance to be cooled. However, this temperaturenormally varies during the reaction and, since the retention time andparticulate or media flow cannot then subsequently be adjusted,unsatisfactory results may be obtained. Furthermore, such variation inretention time and particulate flow cannot be externally controlled.

In addition, multi-stage or plural stage reactors, such as two-stagereactors, require the use of some mechanical valve means between thevarious stages so as to insure isolation between the stages when twodifferent materials are to be operated on independently in separatereactions. Such mechanical means have not been satisfactory.

These disadvantages of the prior art are overcome by the presentinvention.

SUMMARY OF THE INVENTION

A reactor includes means for directing a material, such as a fluid,through the reactor in a predetermined material path. Perforated platemeans, such as perforated trays, are located in the material path andmeans are provided for directing particulate material, such as ceramicbeads, through the perforated plate means and though the material pathin a direction opposite the direction of material flow therethrough forreacting with the material. This flow is normally known ascounter-current flow. The directing means includes means forcontrollably varying the rate of flow of the particulate materialthrough the material path in accordance with variations in apredetermined parameter associated with the reaction, such as theretention time of the particulate material within the material path. Themeans for controllably varying the rate of flow of the particulatematerial preferably includes means for establishing a pile of suchparticulate at the point of introduction of particulate into a givenlocation in the reactor, the pile having an unsupported surface orientedto the horizontal at a predetermined angle of repose of the particulatematerial. Means are also provided for disturbing this angle of reposesuch as by applying to the interior of this pile a stream of fluid toimpel a portion of the particulate material from the outer surfacethereof into the desired location, such as in accordance with variationsin the density of collected particulate material in the pile.

The reactor may be a multi-stage reactor wherein the stages arepreferably sealed from one another by means of particulate materialcollected between stage, the flow from one stage to another beingpreferably regulated by the aforementioned means for controllablyvarying the rate of flow of the particulate material. Thus, theparticulate material, and not a mechanical means, acts as the sealbetween the stages. Each of the stages in such a reactor preferablyincludes a plurality of perforated plates or trays located in thematerial path in each of the reactors. In a two-stage reactor, such asone in which heat exchanges occur, the upper stage may be utilized tocool a hot fluid by means of introducing cool particulate forinteraction therewith and the lower stage may be utilized to recuperatethe heat from the particulate by interaction with a cool fluidintroduced therein, the cooled particulate now being collected at thebottom of the reactor for reintroduction into the upper stage.

Preferably, particulate flow regulators are utilized at one or more ofthe trays in each stage to control the retention time associated withthe particular tray. In addition, the trays are preferably divided intosegments, each segment having an associated particulate flow regulator.Preferably, the particulate flow is related to the fluid flow dependingon the specific heat between the particulate and the fluid such that thespecific heat of the particulate flow on a weight basis is equal to thespecific heat of the fluid flow on a weight basis in order to provideoptimum efficiency for the reactor.

BRIEF DESCRIPTION OF DRAWING

FIG. 1 is a diagrammatic illustration of a preferred embodiment of areactor constructed in accordance with the present invention;

FIG. 2 is a sectional view of a perforated tray of the embodiment shownin FIG. 1 taken along line 2--2;

FIG. 3 is an enlarged fragmentary sectional view of the embodiment shownin FIG. 2 taken along line 3--3;

FIG. 4 is an enlarged partial sectional view of the embodiment shown inFIG. 3 taken along line 4--4;

FIG. 5 is a bottom plan view of the embodiment shown in FIGS. 2 and 3taken along line 5--5 of FIG. 3;

FIG. 6 is an enlarged fragmentary view of a preferred embodiment of aparticulate flow regulator constructed in accordance with the presentinvention;

FIG. 7 is an enlarged fragmentary view of the embodiment shown in FIG.6;

FIG. 8 is an enlarged fragmentary view of the embodiment shown in FIG. 1illustrating the particulate collection portion at the bottom thereof;

FIG. 9 is a fragmentary sectional view of the sealing portion betweenthe two stages of the embodiment shown in FIG. 1 showing an alternativeembodiment thereof;

FIG. 10 is a diagrammatic illustration, similar to FIG. 5, of analternative embodiment of the segmented particulate flow regulatorsassociated with the perforated trays of the embodiment shown in FIG. 1;

FIG. 11 is an enlarged bottom plan view, similar to FIG. 5, of theembodiment shown in FIG. 10; and

FIG. 12 is a fragmentary sectional view, similar to FIG. 7, of analternative embodiment of the particulate flow regulator.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to the drawings in detail, and particularly to FIG. 1thereof, a two-stage reactor, generally referred to by the referencenumeral 20, constructed in accordance with the preferred embodiment ofthe present invention is shown, by way of example and not by way oflimitation. As will be explained in greater detail hereinafter, ifdesired, a reactor having more than two stages or a single stage reactormay be constructed in accordance with the present invention withoutdeparting from the spirit and scope thereof.

TWO-STAGE REACTOR

The two-stage reactor 20 shown in FIG. 1 preferably comprises threesections, an upper section or stage 22, a lower section or stage 24, anda middle section 26 which provides a seal between the upper and lowerstages 22 and 24, as will be described in greater detail hereinafter.For purposes of illustration we shall describe the reactor 20 as a heatexchanger in which thermal interaction occurs although, as will beapparent to one of ordinary skill in the art, any reaction such as achemical reaction may also be accomplished by the interaction ofmaterials in accordance with the present invention. Furthermore, thepresent invention shall be described, by way of example, with referenceto the interaction between a particulate material and a fluid materialwhich is a gas. Such interaction is described by way of example and notby way of limitation as it will become apparent to one of ordinary skillin the art that the interaction could also be between solid and solid,fluid and solid, or fluid and fluid, wherein the fluid could be eithergaseous or liquid.

Preferably, the reactor 20 includes a cylindrical hollow housing 28,although any other desired configuration could be utilized for thehousing 28. As was previously mentioned, the upper stage 22 interior isisolated from the lower stage interior 24 by sealing means 30 providedin the middle section 26. The sealing means 30 preferably comprises aperforated plate 32 extending transversely across the interior of thehousing 28 to separate the interiors of the upper and lower stages 22and 24, respectively. Each of the apertures in the perforated plate 32has an associated collection column 34A, 34B, 34C, 34D, 34E and 34F, sixsuch columns being shown by way of example, for a purpose to bedescribed in greater detail hereinafter. Suffice it to say at this pointthat each of the collection columns 34A through 34F, inclusive, includesan associated particulate flow regulator 36 (only two being shown by wayof example in FIG. 1, the others being omitted for purposes of clarity)to be described in greater detail hereinafter. Suffice it to say thatthe function of the collection columns 34A through 34F and associatedparticulate flow regulators 36, is to provide a seal between the upperand lower stages 22 and 24 by virtue of the particulate materialcollected and densely packed in the collection columns 34A through 34Fand to regulate the distribution or transfer of particulate materialfrom the upper stage 22 to the lower stage 24 while continuing tomaintain the seal between the stages 22 and 24.

The upper stage 22 portion of the housing in the thermal exchanger orreactor being described by way of example includes an inlet 38 for agas, which in the example being described is a hot gas at a highertemperature than the particulate introduced into this stage 22, and anoutlet 40 for this gas after it has been cooled due to the thermalreaction occurring, by way of example, within the upper stage 22. Thelower stage housing portion 24 in the example being described includesan inlet 42 for a cool gas such as air provided at a low temperature orambient which is at a lower temperature than the heated particulateintroduced into this stage 24 from the upper stage 22, the gas beingintroduced such as by means of a conventional fan and blower arrangement44, and an outlet 46 for the gas after it has been heated due to thethermal reaction occurring, by way of example, within the lower stage24. Both the upper and lower stages 22 and 24 preferably contain aplurality of longitudinally spaced apart perforated trays, three suchtrays being shown in each stage by way of example, 50A, 50B and 50C forupper stage 22 and 50D, 50E and 50F for lower stage 24, each of theperforated trays 50A through 50F preferably being identical. Theperforated trays 50A through 50F, which will be described in greaterdetail hereinafter, are shown in greater detail in FIGS. 2 through 5.Suffice it to say at this point that the perforated trays 50A through50F are each respectively mounted by means of an internal lip providedwithin the interior of the respective housing portions 22 and 24, thelip preferably being circumferential. The perforated trays 50A through50F are preferably freely mounted on the respective lips and arepreferably slightly smaller in radial dimension than the radialdimension of the interior of the respective housing portions 22 and 24so as to create a dead space adjacent the interior wall of the housingportions 22 and 24, the lip permitting lateral movement but blockingparticulate flow between trays adjacent the ends of the trays.

As will be described in greater detail hereinafter, each of the trays50A through 50F preferably is divided into segments and each segmentpreferably has an associated particulate flow regulator 36 similar tothe regulator 36 utilized in conjunction with the collection columns 34Athrough 34F, only two such regulators 36 being shown at each tray 50Athrough 50F for purposes of illustration, the others being omitted forpurposes of clarity. However, it is of course understood that, ifdesired, such particulate flow regulators 36 need not be utilized inconjunction with each tray 50A through 50F nor need one be utilized inconjunction with each segment of an associated tray, the location andquantity of the particulate flow regulators 36 associated with theperforated trays 50A through 50F being dependent on the desiredretention time at each tray within the associated stage 22 or 24.Furthermore, if desired, if variations in retention time are permissibleor negligible, then either upper stage 22 or lower stage 24 or both neednot utilize associated particulate flow regulators 36 with the variousperforated trays 50A through 50F therein.

As was previously mentioned, the reaction occurring in reactor 20described by way of example is a particulate-gas fluid interaction forboth upper stage 22 and lower stage 24. As shown and preferred in FIG.1, the particulate material is directed to the top of upper stage 22through a central column or particulate inlet pipe 52 such as by meansof a conventional blower (not shown). The particulate inlet pipe 52 ispreferably coaxial with the longitudinal axis of the reactor 20although, if desired, such inlet pipe 52 need not be coaxial.Preferably, a deflection plate 54 is axially spaced from the outlet end56 of particulate inlet pipe 52 for deflecting particulate supplied frompipe 52 which strikes deflection plate 54, the particulate beingdirected downward towards perforated tray 50A in a fine spray. Ifdesired, the deflection plate 54 need not be utilized but rather theparticulate could be directed out of pipe 52 at exit end 56 at avelocity such that just after exiting from pipe 52 the particulate wouldbe directed downward in a spray due to gravity.

Referring now to FIGS. 6, 7 and 8, a particulate flow regulator 60 isshown. Preferably, the particulate flow regulator 60 is provided at thebottom of reactor 20 beneath the lower stage 24 in communicationtherewith for collecting particulate material which has passed fromupper stage 22 through middle section 26 and then through lower stage 24to the bottom of the reactor 20 for purposes of recirculation of theparticulate material. The particulate flow regulator 60 shown in FIG. 8is utilized to introduce a variable gravity flow of particulate materialinto the pipe 52 and therefrom into the interior of the reactor 20 atexit end 56. Preferably, a gas stream is supplied by means of a blower(not shown) through pipe 55 which is in communication with particulateinlet pipe 52, the gas being supplied at a sufficient velocity topneumatically convey the stream of collected particulate material up thepipe 52 toward the exit end 56 while minimizing contact between theparticulate material and the inner walls of the pipe 52 due to theprovision of a gas buffer between the particulate entrainment zone andaccelerating zone 62. This permits injected gas flow to separate itselffrom particulate flow thereby causing a flow of gas free of particulateto flow upwardly adjacent the inner walls of pipe 52 thereby eliminatingcontact between the particulate and these walls. Preferably, the gasstream has a higher velocity in the particulate entrainment zone portion64 than in the particulate conveying zone portion 62 so as to reversethe inertial force acting on the particulate due to its gravity flowintroduction in the interior of pipe 52 without causing undueparticulate velocity in the conveying zone portion 62, thereby bothreducing abrasion and the energy required to convey the particulate upthe pipe 52.

As shown and preferred in FIG. 8, a concentric hopper 66 is preferablyprovided at the bottom of particle entrainment zone 64 in order tocollect particulate which has not been entrained in the accelerationzone 64. The hopper 66 preferably conducts the collected particulateinto a small diameter duct 68 through which a high velocity gas streamhas been introduced by means of an inlet pipe 70. This preferably causesthe reinjection of this collected particulate at a high velocity intothe acceleration zone 64. The amount of particulate introduced into pipe52 is controllably varied in accordance with a predetermined parametersuch as the density of collected particulate 72. The particulate 72 ispreferably collected at the bottom of the reactor 20 in a funnel shapedportion which produces a pile of particulate material about the exteriorof pipe 52.

As can be seen in FIG. 7, the particulate flow regulator 60 comprises aseries of walls arranged so as to create a pile of particulate materialhaving an unsupported surface oriented to the horizontal at apredetermined angle of repose of the particulate material, such asceramic beads. This angle of repose provides an inclined pile 53 withrespect to the interior of pipes 52 and 55. An inlet pipe 74 is providedin communication with the interior of pile 53 which has thepredetermined angle of repose. A stream of gaseous fluid is suppliedthrough inlet pipe 74 to the pile 53 in order to disturb this angle ofrepose and impel a portion of the particulate material from the outersurface of the pile 53 into the interior of pipes 52 and 55 from whichthis particulate is accelerated up the inlet pipe 52 to be supplied tothe interior of the reactor 20. Thus, by disturbing the angle of reposeof the particulate material, the amount of particulate materialintroduced into the reactor may be controllably varied. Preferably, thisrate of introduction is controllably varied by means of a closedfeedback loop including a sensor means 76 for sensing the gas pressurewithin the collection portion of the particulate flow regulator 60 whichsensor 76 is conventional and generates a control signal in accordancewith variations in this gas pressure, predetermined values of such gaspressure corresponding to predetermined densities of collectedparticulate material, such calibration being conventional.

The closed loop further includes regulation means such as a conventionalvalve 78, for regulating the flow of the stream of fluid introduced tothe interior of pile 53 via inlet pipe 74, the valve 78 beingnresponsive to the control signal supplied by sensor 76 for varying therate of flow of the gaseous fluid stream provided by a convenionalblower 80. In this manner the amount of gaseous fluid supplied to theinterior of pile 53 via inlet pipe 74 and, hence, the amount ofparticulate impelled therefrom, is controllably varied in accordancewith variations in the density of collected particulate material, suchdensity providing an indication of the retention time of the particulatematerial within the reactor 20.

Referring once again to FIGS. 2 through 6, a typical preferredperforated tray 50A is shown. As was previously mentioned, remainingtrays 50B through 50F are all preferably identical therewith and willnot be described in greater detail hereinafter. Since the interior ofthe reactor 20 is preferably cylindrical, tray 50A is preferablycircular and is preferably freely mounted on its associated internallips coaxial with inlet pipe 52 which passes through the center 82thereof. Each of the trays 50A through 50F is preferably fabricated outof a temperature resistant material which can withstand the temperatureof reaction occurring within the associated stages 22 and 24 and whichwill preferably not react with the materials utilized therein.

As was previously mentioned, the weight of the tray is preferably thesole means for holding the tray in position in the interior of thereactor in conjunction with a supporting bracket or lips. In this mannermaintenance is facilitated and temperature expansion is allowed for. Asshown in FIG. 2, the tray 50A preferably comprises a plurality ofsegments, six such segments 88A, 88B, 88C, 88D, 88E and 88F being shownby way of example. Preferably the perforations contained in the tray 50Aand, hence, in each of the segments therein, are sufficiently large topermit the largest particles of the particulate material utilized topass through them and to enable counter-current flow to occur betweenthe particulate material and the gas present in the associated stage 22or 24 for creating a turbulent bed of particulate material on the upperside of the perforated tray 50A. Most preferably, these holes orapertures are in sufficient numbers so as to provide a 25% open area forthe tray although this open area may be from 15% to 75% if desired. Inaddition, each of the segments preferably contains a drain hole orbleeder hole 90A, 90B, 90C, 90D, 90E, and 90F, respectively, preferablylocated at the geometric center of the associated segment. The purposeof the drain hole 90 is to bleed out particulate material from theperforated tray as required for controllably varying the particulateflow to the tray below in conjunction with an associated particulateflow regulator 36 in addition to the normal flow of particulate materialdue to the counter-current flow occurring at the perforations in thetray 50A.

As was previously mentioned, and as was described in U.S. Pat. No.3,263,346, in accomplishing this counter-current flow, the particulatedrifts downwardly towards the plate 50A at a velocity which is less thanthe settling velocity of a particle with no counter air flow. As theparticles approach the plate 50A they are subjected to the relativelyhigh velocity jet action of the gas, such as the gas from inlet 38,passing through the perforations in the plate or tray 50A. Since the jetvelocity is preferably considerably higher than the average particlesettling velocity, the particles are accelerated upwardly until the jetaction of the gas is dissipated. This results in the creation of aturbulent bed above the plate 50A. Because of the spacing of theperforations in the tray 50A, there are quiescent zones above the tray50A in which there is little or no upward gas movement. In these zonesthe particles drift downwardly to the tray 50A where they are againsubject to reentrainment in the gas and flow upwardly or pass throughthe perforations in the tray 50A.

However, as was previously mentioned, in addition to thiscounter-current flow for introducing particles from one tray to theadjacent tray below, the drain holes or bleeder holes 90 enable theoverall rate of particulate flow between trays to be controllably variedin conjunction with an associated particulate flow regulator 36.

PARTICULATE FLOW REGULATOR

Referring now to FIG. 3, a typical particulate flow regulator 36associated with segment 88F is shown by way of example, the arrangementillustrated therein preferably being identical with that associatedrespectively with segments 88A through 88E inclusive. The tray 50A isshown mounted on lip 51. A collection column 92, forming part of theparticulate flow regulator 36 is in communication with drain hole 90Ffor collecting substantially all of the particulate material which isbled through drain hole 90F. The collected particulate material ispacked in collection pipe 92 which preferably has a coaxial disc 94 atthe bottom thereof. The disc 94 and the collection pipe 92 cooperate toform a pile of particulate material having an unsupported surfaceoriented to the horizontal at a predetermined angle of repose of theparticulate material, similar to that illustrated in FIG. 7 andpreviously described. The associated structure of particulate flowregulators 36, which may be identical to that illustrated in FIG. 7, ispreferably that illustrated in FIG. 6. Disc 94, as shown and preferredin FIG. 6, preferably includes an upstanding outer edge or lip and isspaced from the exit end of collection pipe 92 a sufficient distance soas to enable the formation of the pile of particulate material having anunsupported surface oriented to the horizontal at the predeterminedangle of repose of the particulate material.

Preferably, an inlet pipe 96 is in communication with the interior ofdisc 94 and is coaxial therewith, the inlet pipe 96 preferably supplyinga fluid stream to the interior of the pile of particulate materialformed on disc 94, and most preferably a gaseous fluid stream. As isshown and preferred in FIG. 6, the interior of collection pipe 92 isprovided with a peripheral channel for the gaseous fluid stream suppliedthrough inlet pipe 96 which channel enables the input stream to besupplied to the pile of particulate material in order to disturb theangle of repose and impel the portion of the particulate material fromthe unsupported surface towards the next adjacent tray below. Byregulating the gaseous fluid stream supplied via inlet pipe 96, thequantity of particulate material impelled from the unsupported surfaceof the pile may be regulated. As was previously mentioned, this fluidstream may be controllably varied in accordance with the density of thecollected particulate material in pipe 92 in the manner previouslydescribed with reference to FIG. 7. Preferably, the rate of flow of theparticulate material is controlled in the manner previously describedwith reference to FIG. 7, such as by a closed feedback loop, and willnot be described in greater detail hereinafter, the associated circuitrybeing omitted for purposes of clarity.

As shown and preferred in FIG. 4, inlet pipe 96 is preferably protectedfrom abrasion by means of providing upwardly extending lips 100 and 102along the length of the transversely extending portion of inlet pipe 96,the upwardly extending lips 100 and 102 serving to initially collectparticulate material on the upper exposed outer surface of the pipe 96and thus prevent subsequent abrasion of this surface of pipe 96 due tothe buffer provided by the collected particulate material.

As shown and preferred in FIG. 5, the plurality of particulate flowregulators 36 are preferably arranged on a circular pipe 104 which is incommunication with inlet pipe 96 to simultaneously supply the fluidstream to all of the associated particulate flow regulators 36. In thearrangement shown in FIG. 5, upwardly extending lips 100 and 102 areprovided on the circular pipe 104 for protecting the surface of thispipe from abrasion in the manner previously described with reference toFIG. 4. If desired, in place of the preferred arrangement illustrated inFIG. 5, the particulate flow regulator 36 and the associated inlet pipestherefor may be arranged in the manner illustrated in FIG. 10, in whichinstance the particulate flow regulators and associated inlet pipes ateach tray level will appear as illustrated in FIG. 11

Referring once again to FIG. 1, the particulate flow regulator 36associated with the collection pipes 34A through 34F inclusive whichenable the sealing of the upper stage 22 from the lower stage 24 bymeans of the densely packed particulate material collected therein,preferably function in the same manner previously described above withreference to the particulate flow regulator 36 associated with eachsegment of the tray 50A and have been given the same reference numeral.In addition, the rate of flow of particulate material through theassociated collection pipes 34A through 34F inclusive is controllablyvaried, preferably, in the manner previously described with reference toFIG. 7 wherein the sensor 76 senses the pressure of the gas within theassociated collection pipe 34A, by way of example, and generates acontrol signal in accordance therewith which control signal operates avalve 78 which controls the rate of flow of the gaseous fluid fromblower 80 supplied via inlet pipe 96 to the interior of the pile formedon disc 94 for disturbing the angle of repose and impelling the portionof the particulate material from the surface of the unsupported pile. Aswas previously mentioned, this pressure is calibrated in accordance withthe density of collected particulate material. If desired, in place ofthe closed feedback loop previously described, an ON-OFF switch could beprovided to shut off or turn on the supply of gaseous fluid to theregulator 36 or, if desired, an associated alarm could be provided whichwould be activated when the pressure dropped below a predeterminedlevel.

If desired, in place of the plurality of collection pipes 34A through34F shown and preferred in FIG. 1, a single centrally located collectionpipe, preferably having a volume equivalent to the total volume ofcollection pipes 34A through 34F could be provided, as shown in FIG. 9.The particulate flow regulator 36 associated therewith is preferablyidentical with that previously described with reference to the pluralityof collection pipes 34A through 34F and preferably only differs in termsof size, although being preferably identical in terms of operation.

OPERATION OF TWO-STAGE REACTOR

By way of example, the operation of the two-stage reactor 20 constructedin accordance with the preferred embodiment of thee present inventionshall now be described in greater detail. As was previously described,for purposes of illustration, the operation of reactor 20 shall bedescribed as a two-stage heat exchanger in which thermal interactionoccurs although, as will be apparent to one of ordinary skill in theart, any reaction such as a chemical reaction may also be accomplishedby the interaction of materials in accordance with the presentinvention. Furthermore, as was also previously described, this operationwill be described, by way of example, with reference to the interactionbetween a particulate material and a gaseous fluid material although, aswill also be apparent, the particulate could consist of at least twoportions instead of one portion, such as a chemically active ingredientsuch as dolomite for collecting sulfur dioxide if that is the desiredreaction and a flow characterization portion such as a scouring agent ifit is desired to circumvent the shortcomings of such a chemically activematerial. In addition, the fluid material need not be gaseous and theinteraction could be between solid and solid, fluid and solid, or fluidand fluid wherein the fluid could be either gaseous or liquid or, ifdesired, a slurry could be utilized.

Now describing the operation of reactor 20 with reference to the thermalinteraction between the gas and the solid particulate in both the upperstage 22 and the lower stage 24. By way of example, the lower stage 24has a relatively cool gas, such as 150° Fahrenheit to 200° Fahrenheit orambient, supplied thereto through inlet 42. The upper stage 22 in thisexample has hot gas, such as at a temperature of 1,600° Fahrenheit,supplied thereto via inlet 38. As was previously described, theparticulate material is directed to the top of upper stage 22 throughthe particulate inlet pipe 52, such as by means of a conventionalblower. By way of example, the particulate directed through pipe 52strikes deflection shield 54 and is directed downwardly towardsperforated tray 50A in a fine spray. The hot gas within upper stage 22interacts with the fine spray of particulate material directed throughthe fluid path of the gas in a thermal interaction wherein the gas iscooled and the particulate is heated due to conventional heat transfer.

At each of the perforated trays 50A through 50F, inclusive, a turbulentbed of particulate material is formed in a fashion similar to thatdescribed in U.S. Pat. No. 3,263,346 wherein as the particulate driftsdownwardly towards the associated perforated tray at a velocity which isless than settling velocity of a particle with no counter-current airflow, it is subjected to the relatively high velocity jet action of thegas within the appropriate stage 22 or 24 passing through theperforations in the associated perforated tray 50. As was alsopreviously mentioned, the jet velocity is preferably considerably higherthan the average particle settling velocity and, accordingly, theparticles are accelerated upwardly until the jet action of the gas isdissipated which results in the creation of the turbulent bed above therespective perforated tray. Because of the spacing of the perforationsin the associated perforated tray, there are quiescent zones above thetray in which there is little or no upward air movement. In these zonesthe particles drift downwardly to the tray where they are again subjectto reentrainment in the gas and flow upwardly or pass through theperforations in the tray 50. At each of these perforations, the gaspasses upwardly through the perforations and is contracted towards thecenter of the aperture, thus allowing particles of material to flowdownwardly through the aperture at the sides thereof. If the flow ratethrough the aperture is not sufficient to accommodate all the particlespresenting themselves to the aperture without blocking the aperture, thegas flow is temporarily cut off and is transferred to another unblockedaperture. As soon as the gas flow stops, the temporarily retainedparticles are released until blockage is eliminated and the gas flow isreestablished through the aperture.

The particles of material pass downwardly through the closest adjacentperforated tray and into another turbulent bed from above the perforatedtray immediately below wherein the action described above is repeated.However, in addition to the normal flow of particulate through theperforations, the passage of the particulate from one turbulent bed tothe next adjacent turbulent bed is controllably regulated by means ofthe particulate flow regulators 36 at each perforated tray.

As was previously mentioned, in addition to the normal perforations,bleeder holes or drain holes 90A through 90F are provided at each trayat the geometric center of the tray segments 88A through 88F,respectively. In this manner the amount of particulate being introducedinto the fluid path above the next adjacent perforated tray immediatelybelow is controllably varied.

As was also previously mentioned in describing the associatedparticulate flow regulators 36, the manner of controlling the amount ofparticulate flow is by means of disturbing the natural angle of reposeof the collected particulate material in collection pipe 92 by supplyinga stream of gaseous fluid through associated inlet pipe 96 to theinterior of the pile of particulate material collected on each of thediscs 94 in order to disturb the angle of repose and impel a portion ofthe particulate material from the outer surface of the pile into theadjacent fluid path and subsequently to the perforated tray below.Preferably, as was also previously mentioned, this rate of introductionis controllably varied by means of a closed feedback loop wherein thegas pressure within the collection portion of the particulate flowregulator is sensed by conventional means and generates a control signalin accordance with variations in this gas pressure, predetermined valuesof such gas pressure corresponding to predetermined densities ofcollected particulate material (the calibration being conventional),this control signal being utilized to control a valve for regulating theflow of the stream of fluid introduced to the interior of the pilethrough pipe 96. By controllably varying the amount of particulateimpelled from the pile in accordance with variations in the density ofthe collected particulate material, the retention time of theparticulate material at the associated location in the reactor 20 of theassociated tray 50 and flow regulator 36 and, hence, within the overallreactor 20 may be controllably varied.

Thus, if desired, at each perforated tray, and at each segment 83thereof, the retention time of the particulate material may becontrollably varied. The operation of the associated particulate flowregulators 36, as was previously mentioned, is in addition to the normalflow of particulate material due to the counter-current flow occurringat the perforations in the associated trays 50. It should be noted thatpreferably the particulate flow is related to the gas flow in accordancewith the specific heat between the particulate and the associated gasessuch that the specific heat of the particulate flow on a weight basis isequal to the specific heat of the gas flow on a weight basis in order toobtain optimum efficiency in the reactor 20.

As the particulate passes from one turbulent bed to the next adjacentturbulent bed below, and interacts with the gaseous fluid, the gas iscooled at each level or tray in stages so that at the uppermost tray, inthis instance 50A, the gas is at the desired cooled temperature, theparticulate being heated to a desired temperature as a result of thisinteraction prior to passing into middle section 26 which seals theupper and lower stages 22 and 24, respectively. Continuing with thisexample, the particulate material passing downwardly through theperforated trays 50A through 50C via normal counter-current flow as wellas particulate flow regulation within the fluid path, passes throughperforated plate 32 and into the associated collection columns 34Athrough 34F which densely pack the collected particulate materialtherein so as to provide a seal between upper stage 22 and lower stage24, such seal being due preferably only to the densely packedparticulate within the associated collection pipes 34.

As was previously mentioned, each of the collection columns or pipes 34includes an associated particulate flow regulator 36 whose operation issimilar to that previously described with reference to the particulateflow regulators 36 utilized in conjunction with the perforated trays 50and, thus, will not be described in greater detail hereinafter. Sufficeit to say, that the associated particulate flow regulators 36 associatedwith the collection columns 34 enable the provision of a seal betweenthe upper and lower stages 22 and 24 by virtue of the particulatematerial collected and densely packed in the collection columns 34 whileregulating the distribution or transfer of particulate material from theupper stage 22 to the lower stage 24 while continuing to maintain thisseal between the stages 22 and 24.

In the example being described, particulate material, which has beenheated due to the thermal interaction occurring in the upper stage 22,is introduced into the fluid path in lower stage 24 above perforatedtray 50D by means of the associated particulate flow regulators 36associated with the collection columns 34. Subsequently, in the mannerpreviously described above with reference to perforated tray 50A, aturbulent bed is formed above perforated tray 50D and, in the mannerpreviously described, due to normal counter-current air flow as well asparticulate flow regulation at the various segments 88 of the associatedperforated tray, the heated particulate is directed through the gaseousfluid path of the introduced cool gas which is subsequently heated as itpasses upwardly through each of the perforated trays 50F, 50E, and then50D and, subsequently, to exhaust or outlet pipe 46, the mechanicaloperation of lower stage 24 preferably being identical with that ofupper stage 22, the primary difference being that the reactionsoccurring in each of the stages 22 and 24 are thermodynamicallyreversed. Preferably, the perforated trays 50D through 50F and theretention time of the particulate material in lower stage 24 iscontrollably varied so as to enable the heated particulate materialsubsequently passing through the perforated trays 50D, 50E and 50F to becooled back to approximately its original temperature at which it wasintroduced into upper stage 22 upon its entering the bottom of thereactor 20, the introduced cool gas being heated prior to exhaustionthrough outlet pipe 46, in the example given due to interaction with theheated particulate introduced into lower stage 24 via collection columns34 and associated particulate flow regulators 36.

The recirculation of the particulate material collected at the bottom ofreactor 20 is preferably controllably varied by means of particulateflow regulator 60 whose operation has been previously described withreference to FIGS. 6, 7 and 8. Suffice it to say that the natural angleof repose of the collected particulate material is disturbed in order topermit gravity flow within the gap formed between the pipes 52 and 55 soas to impel a portion of the outer surface of the pile 53 into theparticle entrainment zone. If desired, however, no such regulation meansneed be utilized with respect to the recirculation of the collectedparticulate material which may just be collected at the bottom of thereactor 20 and pneumatically fed into particulate inlet pipe 52 in astream which is of sufficient velocity to strike deflection shield 54and deflect the particulate downwardly towards perforated tray 50A in afine spray once again.

By way of example, a typical two-stage reactor similar to reactor 20having the following parameters may be utilized in accomplishing thepresent invention wherein, in the lower stage 24, a cooled gas which isintroduced at inlet 42 either at ambient or a temperature ofapproximately 150° Fahrenheit to 200° Fahrenheit is heated to atemperature of approximately 1,400° Fahrenheit at which it is exhaustedthrough outlet 46 while cooling heated particulate from upper stage 22which is introduced into lower stage 24 at a temperature ofapproximately 1,500° Fahrenheit, due to the thermal reaction occurringin the upper stage 22, to an original temperature of approximately 250°Fahrenheit, the particulate being introduced into the upper stage 22 atan original temperature of approximately 250° Fahrenheit cooling a gasintroduced at inlet 38 at a temperature of approximately 1,600°Fahrenheit to a temperature of approximately 300° Fahrenheit where it isexhausted via outlet 40. In such an example, the particulate shouldpreferably consist of 1/8 inch diameter alumina ball, the trays 50should preferably have 3/4 inch perforations providing a 25% open areaand 11/4 inch drain holes 90, with 3 inch diameter plates or discs 94being utilized with flow regulators 36 having an associated nozzlevelocity of 5 CFM per nozzle, the spacing between the three perforatedtrays 50 in each of the stages 22 and 24 preferably being between 12inches and 18 inches, the diameter of the reactor 20 preferably being 8feet, the flow velocity of the particulate preferably being 900 poundsof particulate per minute circulation, the flow velocity of the gas ineach of the stages preferably being 900 pounds of gas per minutecirculation, and the air pressure from the associated particulate flowregulator nozzle preferably being injected at a pressure of 5 inches to6 inches W.C. pressure. It should be noted that 0 CFM through 10 CFM ofnozzle in the preferred particulate flow regulator 36 could preferablycontrol 0 to 10 tons per hour of particulate flow in the preferredembodiment of the present invention.

It should also be noted that if desired, water could be injected intosuch a reactor to provide low pressure steam directly; slurry could beinjected at certain temperature levels in the reactor, the temperaturelevels being determined by the perforated tray and the retention time atthat tray, to obtain a desired chemical reaction; heat accumulationcould be provided in such a reactor through the accumulation of hightemperature particulate such as by providing a difference in theoperating rate of BTU release between the upper and lower stages 22 and24; or the particulate could be a catalytic agent for causing a desiredchemical reaction, as well as many other utilizations too numerous tomention, but which will become apparent to one of ordinary skill in theart.

It should be noted that preferably, both the gas introduced into thelower chamber 24 and the gas introduced into the upper chamber 22 arepreferably introduced through pipes having a plurality of aperturestherein for introducing the gas in a plurality of jet velocity streams,such as through slits in a cover plate.

By utilizing the present invention the retention time associated withthe various levels in a reactor, such as at the perforated traysthereof, as well as the overall retention time within the reactor, maybe controllably varied in accordance with any desired predeterminedparameters associated with the reaction occurring within the reactor andthus, instabilities which may occur in such a reaction can be externallycompensated for without the necessity of changing the presizedperforated trays. In addition, many other advantages will occur to oneof ordinary skill in the art.

It is to be understood that the above described embodiments of theinvention are merely illustrative of the principles thereof and thatnumerous modifications and embodiments of the invention may be derivedwithin the sprit and scope thereof.

What is claimed is:
 1. An apparatus for controllably introducingparticulate material into the interior of a hollow reactor housing in apredetermined particulate material flow path having a predetermineddirection of flow therethrough assisted by gravity in the direction of adesired process path of reaction within said reactor for enabling saidreaction of said flowing particulate material within said process path,said apparatus comprising means for injecting said particulate materialinto said gravity assisted flow path within said housing interior, awalled chamber means disposed within said housing interior at a firstpredetermined level within said process path and having an inlet endthereof disposed in flow path communication with said injection meansfor intercepting said injected particulate material and collecting saidintercepted particulate material within said walled chamber through saidinlet end thereof, said walled chamber having a first walled inletportion at said inlet end for initially collecting said interceptedmaterial therewithin, said inlet portion having a first internaldiameter, said walled chamber further comprising a second walled outletportion connected to said inlet portion and having an upstanding wallwith a base portion at the bottom thereof for collecting said materialthereon, said outlet portion having a greater internal diameter thansaid inlet portion internal diameter with said inlet and outlet portionsbeing spaced apart to form an angulated outlet for said chamber alongsaid upstanding wall thereof, said spacing between said inlet and outletportions of said walled chamber establishing a pile of said collectedintercepted particulate material therewithin at said first predeterminedlevel having an unsupported surface oriented to the horizontal betweensaid spaced apart inlet and outlet portions at said first predeterminedlevel at a predetermined natural angle of repose of said particulatematerial within said walled chamber which natural angle of reposedefines an equilibrium condition for said collected particulate materialpile, said walled chamber angulated outlet disposed along saidunsupported surface, and means disposed within said collectedparticulate material pile at said first predetermined level fordisturbing said natural angle of repose equilibrium conditionirrespective of any fluidization characteristic of said collectedparticulate material for impelling a portion of said collectedintercepted particulate material at said first predetermined level fromsaid unsupported oriented surface through said outlet toward a secondpredetermined level within said process path, said disturbing meanscomprising means disposed within the interior of said collectedparticulate material pile substantially at the location of saidangulated outlet for introducing a thin stream of fluid from within saidcollected particulate material pile at said angulated outlet location inthe same direction as said predetermined direction of particulatematerial flow, whereby said fluid stream optimally disturbs saidequilibrium condition to control the retention time of said collectedintercepted particulate material within said process path at said firstpredetermined level independently of any fluidization characteristics ofsaid collected particulate material pile.
 2. An apparatus in accordancewith claim 1 wherein said collected particulate material has apredetermined density corresponding to a predetermined quantity ofparticulate material for said impelled portion thereof, said fluidintroducing means including means disposed within said chamber forcontrollably varying the rate of flow of said stream of fluid inaccordance with variations in said density.
 3. An apparatus inaccordance with claim 2 wherein said fluid stream rate control meanscomprises a closed feedback loop including sensor means located withinsaid chamber for sensing the gas pressure within said chamber andgenerating a control signal in accordance with variations in such gaspressure, predetermined values of said gas pressure corresponding topredetermined densities of said collected particulate material, andregulation means for regulating the rate of flow of said stream of fluidoperatively connected to said sensor means, said regulation means beingresponsive to said control signal for varying the rate of flow of saidfluid stream in accordance therewith.
 4. An apparatus in accordance withclaim 1 wherein said collected particulate material has a predetermineddensity corresponding to a predetermined quantity of particulatematerial for said impelled portion thereof, said fluid introducing meansincluding means disposed within said chamber for controlling the rate offlow of said stream of fluid in accordance with variations in saiddensity.